What is the purpose of react-helmet?
I've created a server-side react app, where it would return html as shown below:
const html = renderToString(<App />);
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0">
<title>A Cool Page</title>
<link rel="stylesheet" href="${ROOT}/static/index.css">
</head>
<body>
<div id="root">${html}</div>
<script src="${ROOT}/client-bundle.js"></script>
</body>
</html>
I read a lot of people have been using react-helmet to manage the content in head. I'm wondering what's the benefit of using it, when I can just directly include as shown above.
Answer
A major benefit or react-helmet is when you have multiple components in a tree with <head> tags, and you have <meta> tags with the same attributes/values.
For instance, if on your index page component you have:
const html = renderToString(<App />);
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0">
<meta name="description" content="This is the index page description">
<title>A Cool Index Page</title>
</head>
</html>
But then on a leaf page component, you also have a <head> tag containing meta tags:
<html>
<head>
<meta name="description" name="This is the unique leaf page description">
<title>A Cool Leaf Page</title>
<link rel="stylesheet" href="${ROOT}/static/index.css">
</head>
</html>
Notice between our two page components there are two meta tags with the same attribute value name="description" in our tree. You might think this could lead to duplication, but react-helmet takes care of this problem.
If someone ends up on the leaf page, react-helmet overrides the index/site-level description meta tag and renders the lower-level one, the one specifically for the leaf page.
It will also contain the viewport meta tag, since it did not have to be overwritten.
Because of react-helmet, on the leaf page, the <head> would appear as follows:
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0">
<meta name="description" name="This is the unique leaf page description">
<title>A Cool Leaf Page</title>
<link rel="stylesheet" href="${ROOT}/static/index.css">
</head>
</html>